EP1832730B1 - Turbo charger with convection cooling system - Google Patents

Abstract

The engine (15) has a turbocharger (1) attached at a turbocharger supply system and at a turbocharger-return system for discharging coolant warmed in the turbocharger to a coolant circuit. The supply system between a water pump-outlet connection and a radiator-supply system is deviated from a cooling water circuit. The turbocharger-return system is opened in the area of a cooling water circuit provided between a radiator-return system and a water pump-inlet connection, where a water level of a compensation tank (9) is higher than the supply system and the turbocharger-return system.

Description

The invention relates to an internal combustion engine with a turbocharger, with a cooling water circuit and with a surge tank for the cooling water circuit.

From the publication EP 0 160 243 B2 Such a cooling system is known for an internal combustion engine with a turbocharger, in which a Torbolader cooling water circuit cooperates with an engine cooling water circuit.

An internal combustion engine is in the US 4,561,387 shown. In this internal combustion engine is disadvantageous that damage to the turbocharger may occur if the proposed there solenoid valve between reservoir and turbocharger malfunctions.

The US 4 107 927 shows an internal combustion engine with a turbocharger, which is included in the cooling water circuit of the internal combustion engine. Design requirements are opposed to a realization of this concept in modern internal combustion engines.

The JP 2 045 617 shows a device in which after switching off the ignition of an internal combustion engine, this is operated for a certain time at idle until the turbocharger has been sufficiently cooled. This requires sensors and electronics.

The JP 5 9224 414 shows an internal combustion engine having an additional separate cooling circuit including radiator for the cooling of turbocharger and cylinder head. The engine block of the internal combustion engine is cooled in a primary cooling circuit.

The DE 2 825 945 shows an internal combustion engine in which the turbocharger is supplied with the motor running with a pressure generated by the water pump with coolant. After switching off the engine, the cooling water circuit stops, which can lead to overheating of the turbocharger.

One of the problems underlying the invention is to ensure sufficient cooling of the turbocharger immediately after stopping the engine. If this is not ensured, then damage may result, as described in more detail in the prior art.

The invention is therefore based on the task of providing an internal combustion engine in which the turbocharger is always sufficiently cooled.

This object is solved by the subject matter of the independent patent claims. Advantageous developments emerge from the dependent claims.

The invention provides a turbocharger whose turbocharger flow diverges between the water pump output port and the radiator flow from the cooling water circuit. This will ensure that the turbocharger is supplied with pressurized cooling water. This ensures good cooling of the turbocharger during normal operation of the internal combustion engine.

The turbocharger return flows into a region of the cooling water circuit between the radiator return and the water pump inlet port in the cooling water circuit. As a result, the turbocharger is subjected to negative pressure, which is generated by the water pump. This results in an improved flow through the turbocharger with cooling water.

To improve the cooling of the turbocharger with the engine stopped, when the water pump does not deliver cooling water, the turbocharger return is via a vent line with the surge tank in combination. The water level of the partially filled with air surge tank is geodetically higher than the turbocharger return. This embodiment ensures that a flow is started which cools the turbocharger, even if the water pump does not deliver any cooling liquid. This is attributed to a convection effect. Furthermore, the steam generated in the turbocharger water space is discharged to the expansion tank.

Without this vent hose, the turbocharger water space would fill with steam and the cooling would be interrupted. The design according to the invention ensures that the turbocharger is reliably cooled in the event of afterheating when the engine is switched off. The cooling effect is similar to the operation of a coffee machine, in which a water vapor-water mixture is conducted due to heating up. The acting at the lower level back pressure, which allows the Hochfördern is formed according to the invention by the pending at the turbocharger feed water volume.

The invention can also be implemented in that the turbocharger supply via a degassing line with the expansion tank communicates. Then the water level of the expansion tank must be higher than the turbocharger flow. The resulting in the shutdown of the internal combustion engine in the turbocharger in the water chamber gas in the form of water vapor is then discharged through the degassing into the expansion tank, while the water content is returned to that portion of the cooling water circuit, which communicates with the turbocharger flow.

By contrast, it would also be possible to connect the turbocharger feed with a hose to the radiator return, wherein the turbocharger return is connected with a hose to the expansion tank. It is also possible to connect the turbocharger feed with a hose to the cooling water circuit in the internal combustion engine, wherein the turbocharger return is connected with a hose to the expansion tank.

Furthermore, it is possible to connect the turbocharger feed with a hose to the water circuit in the internal combustion engine, while the turbocharger return is connected with a hose to the thermostat housing or to the suction side of the water pump. This embodiment can also be configured with an electric auxiliary pump in the flow tube of the turbocharger.

These deviating from the invention embodiments have not proven. In some of these embodiments, the water flow rate through the turbocharger is too low because of too low a differential pressure between the radiator outlet and the surge tank. When the engine is stopped, the cooling of the turbocharger is weak because hoses have to be laid unfavorably due to design requirements and the degassing situation. When the expansion tank with in the cooling circuit of the Turboladers is included, there must be made expensive additional measures to avoid foaming. Such additional measures in turn lead to an increase in the flow resistance in the expansion tank, which deteriorates the cooling of the turbocharger with the engine stopped. If the turbocharger forcibly acted upon by the water pump of the cooling circuit, then there is indeed a high water flow rate and good cooling with the engine running. However, when the engine is stopped, the cooling is so bad that turbocharger damage often occurs. A dedicated additional pump is costly and prone to failure and should therefore be avoided.

The invention goes with a clever combination of measures another way, resulting in a reliable cooling of the turbocharger both during operation of the internal combustion engine and after stopping the engine. Unacceptable temperatures are avoided, as well as unwanted Ölverkokung in the bearings of the turbocharger and thus increased wear. With the invention, the requirements for the boundary conditions for the operation of a turbocharger can be easily met, so that any damage to the turbocharger can be attributed to causes that are related to the production of the turbocharger. The invention dispenses with additional moving parts such as a postheat pump, furthermore, overpressures are avoided in the cooling system, which can lead to a water vapor outlet and possibly to a Kühlwas-serverlust.

In one development of the invention, the turbocharger supply line is connected to a coolant channel extending in the region of an engine block of the internal combustion engine or even to a coolant channel extending in the engine block itself is. This results in regular reliable flow through the turbocharger with coolant, which is pumped at high pressure through such channels to ensure good cooling of the engine block.

Deviating from this, the turbocharger flow can also be connected to a mounted on the engine block thermostat housing, be. This ensures a simple construction and final assembly.

Especially in tight spaces, the turbocharger return can open into a further connected to the coolant circuit Heizradiator return. In certain embodiments, this ensures good turbocharger after engine stop when the turbocharger is supplied with cooling water from the heating system via its turbocharger return.

It has been proven to provide the turbocharger return line between a point at which the Heizradiator return flows into a Heizradiator, and a point at which the Heizradiator return flows in a thermostat connected to the Heizradiator return (37) is, especially in the event that the thermostat is located in the water pump inlet.

The turbocharger return can also lead to a connected to the coolant circuit water pump return or in a further connected to the coolant circuit oil cooler supply. Depending on the installation space, this may be necessary to obtain small dimensions of the cooling system.

It should be sought, the degassing as possible in the region of the highest point of the connecting line between the turbocharger return and to let the coolant circuit branch off the connecting line. This ensures that air bubbles easily separate from the coolant without, for example, the convection flow is obstructed by the air bubbles. Depending on the configuration of the cooling system, it may be necessary that the degassing line branches off from this connecting line in the region of the highest point of the connecting line between the turbocharger return line and the coolant circuit or between the turbocharger supply line and the coolant circuit.

The invention can also be applied to internal combustion engines in which the flow of the turbocharger with throttles is limited, especially when the turbocharger is connected near the output port of the water pump. Then it may be necessary to provide the line to the turbocharger flow, the line from the turbocharger return and the degassing, each with a throttle for adjusting the flow resistance for the cooling liquid to ensure the flow through the other components of the cooling system with coolant.

The invention is also realized in a motor vehicle with such an internal combustion engine.

Figur 1

zeigt eine schematische Darstellung eines gemäß der Erfindung gekühlten Turboladers,

Figur 2

zeigt eine schematische Darstellung eines Kühlmittelkreislaufs eines Verbrennungsmotors, an dem die Erfindung verwirklicht ist,

Figur 3

zeigt eine schematische Darstellung eines Kühlmittelkreislaufs eines weiteren Verbrennungsmotors, an dem die Erfindung verwirklicht ist.

The invention is illustrated by means of embodiments in the drawing.

FIG. 1

shows a schematic representation of a cooled according to the invention the turbocharger,

FIG. 2

shows a schematic representation of a coolant circuit of an internal combustion engine, on which the invention is realized,

FIG. 3

shows a schematic representation of a coolant circuit of another internal combustion engine, on which the invention is realized.

FIG. 1 shows a schematic representation of the cooling of a turbocharger 1 of an internal combustion engine not shown in detail in this view with a cooling circuit, also not shown.

The turbocharger 1 has a turbocharger feed 2 and a turbocharger return 3. Here, a feed line 4 is connected between a water pump outlet port and a radiator flow to the coolant circuit of the internal combustion engine. To the turbocharger return 3, an output line 5 is connected, which leads to a tee 6. One of the other two terminals of the T-piece 6 is connected to a return line 7, which opens in a region of the coolant circuit between the radiator return and the water pump Eingartgsanschluss the internal combustion engine. The remaining connection of the T-piece 6 is connected to a degassing 8, which leads to a surge tank 9, above a water level 10 in the expansion tank 9. At the bottom of the surge tank 9, a compensation line 11 is connected, which leads to the coolant circuit of the engine ,

As you can see particularly well in this view, the water level 10 is above the turbocharger. 1

During normal operation of the internal combustion engine, the turbocharger 1 is supplied with pressurized water, via the supply line 4 and via the return line 7. The internal combustion engine turned off, then formed due to the high temperatures of the turbocharger 1 gas bubbles inside the turbocharger 1. This is in Fig. 1 illustrated by drawn gas bubbles in the output line 5 and the turbocharger 1. Due to the gas bubbles, the coolant located in the interior of the turbocharger 1, in the feed line 4 and in the outlet line 5 is conveyed upwards, up to the area of the T-piece 6, which is advantageously at a relatively high point from the outlet line 5 and return line 7 is arranged. At the T-piece 6, the gas bubbles separate from the coolant, because they escape through the degassing 8 into the expansion tank 9. There condenses the water vapor contained in the gas bubbles and the auskondensierte coolant is returned to the cooling circuit. Likewise, with the gas bubbles mitbefördertes coolant is returned to the surge tank 9 and thus in the cooling circuit of the engine.

FIG. 2 shows a schematic representation of the cooling system of an internal combustion engine 15, where the in FIG. 1 described turbocharger is provided. The internal combustion engine 15 is designed here as a V-type engine with a first row of cylinders 16 and with a second row of cylinders 17. A water pump 18 having a water pump input port 20, a first water pump output port 21 for the first cylinder bank 16, and a second water pump output port 22 for the second cylinder bank 17.

The coolant flow in the internal combustion engine 1, which is generated by the water pump 18 is illustrated with directional arrows.

The coolant outlets of the first row of cylinders 16 and of the second row of cylinders 17 are brought together in a ridge line 23. From there, the cooling water flow enters a radiator inlet line 24 from and into a radiator flow 25 of a radiator 26 a. In the radiator 26, a radiator return 27 is provided, which is connected via a radiator return line 28 with a thermostat 29. From the thermostat 29 performs a water pump line 30 to the water pump 18 back. A short-circuit line 31 connects the thermostat 29 to the land line 23.

By this arrangement, the coolant circuit of the internal combustion engine 15 is predetermined.

When starting the engine 15 in the cold state, the thermostat 29 closes the connection between the radiator return line 28 and thermostat 29. At the same time, the connection between the short-circuit line 31 and the thermostat 29 is opened. Coolant then circulates from the water pump 18 into the first row of cylinders 16, into the second row of cylinders 17 and into the line 23. From there, the coolant is fed into the short line 31, to the thermostat 29 and from there via the water pump line 30 back to the water pump 18 ,

When the coolant heats up, the thermostat 29 closes the connection between the shorting line 31 and the thermostat 29, at the same time the connection between the radiator return line 28 and the thermostat 29 is opened. The coolant then flows from the riser 23 into the radiator feed line 24 and into the radiator run 25. It is cooled in the radiator 26 and takes its way via the radiator return 27 and the radiator return line 28 to the thermostat 29 There it is conveyed back to the water pump 18 via the water pump line 30.

To the cooling circuit described above, a plurality of auxiliary units are connected, such as an oil cooler 32, a Heizungsradiator 33, the surge tank 9 and the turbocharger 1. In this case, the oil cooler 32 is supplied via an oil cooler inlet line 34 with coolant from the radiator feed line 24. The coolant heated in the oil cooler 32 is returned to the radiator return line 28 via an oil cooler drain line 35.

The Heizungsradiator 33 is supplied with coolant, which is taken at a location of the web lead 23. From there it is fed via a Heizungsradiator supply line 36 to the Heizungsradiator 33. The coolant cooled in the heating radiator 33 is returned to the thermostat 29 via a heating radiator return line 37. From the Heizungsradiator-return line 37 branches a compensation line 38 to the bottom of the surge tank 9 from. Furthermore, the return line 7 is connected from the T-piece 6 to the Heizungsradiator-return line 37.

A vent line 39 extends between the bridge line 23 and the surge tank 9, wherein the expansion tank 9 facing the end of the vent line 39 forks into a above the water level 10 opening gas line 40 and into a below the water level 10 opening coolant line 41.

The flow line 4 to the turbocharger 1 is connected to a coolant outlet 42 second row of cylinders 17 to the coolant circuit. With a properly sized flow restrictor 43 of the flow resistance of the flow line 4 is set so that the turbocharger 1 is supplied with sufficient coolant during normal operation of the engine 15. With a degassing throttle 44 in the degassing 8 whose flow resistance is set. During operation of the internal combustion engine 15, the degassing throttle 44 has the task of counteracting the excessive inflow of coolant from the turbocharger return 3 to the expansion tank 9. When the internal combustion engine 15 is stationary, when gas bubbles form in the turbocharger 1, the vent throttle 44 causes, above all, water vapor to escape into the expansion tank 9 and not so much coolant.

In an embodiment not shown here, the design can FIG. 2 be essentially taken over. In from the in FIG. 2 As shown, the return line 7 is not connected to the Heizungsradiator-return line 37, but the thermostat 29, to the water pump line 30 or equal to the water pump 18. The supply line 4 can also be connected to the web line 23 or to the radiator feed line 24 , The flow restrictor 43 and the degassing throttle 44 can also be designed as variably adjustable throttles.

In another example, not shown here, in which a thermostat is not connected to the motor input, as in FIG. 2 but rather at the engine outlet, the return line 7 can be connected to the radiator return line 28.

With the above variants it is ensured that the turbocharger 1 is always flowed through with coolant, wherein it is not important which lines the thermostat 29 just opens or blocks.

In another embodiment, not shown here are in the in FIG. 2 shown representation of the points where the return line 7 and the Heizungsradiator-return line 37 open into the equalization line 38, as close to each other. As a result, a return flow in the line 38 is reduced or completely avoided at high engine speeds.

FIG. 3 shows a schematic representation of another internal combustion engine 45, which is designed as a four-cylinder with a single cylinder row 46. Parts with the same function are in FIG. 3 denoted by the same reference numerals as in FIG. 1 and in FIG. 2 , but they are provided with an apostrophe.

When starting the engine 45 in a cold state, the thermostat 29 'is closed. The coolant therefore circulates from the water pump 18 'into the cylinder bank 46, thence into the heater radiator supply line 36', through the heater radiator 33 ', back into the heater radiator return line 37', thence into the oil cooler 32 'and back into the Water pump inlet port 20 '. In this case, coolant flows from the thermostat 29 '"to the T-piece 6' and from there via the feed line 4 'to the turbocharger 1'. The coolant in the turbocharger 1 'is sucked into the radiator return line 28 via the outlet line 5' the action of the water pump 18 'communicating with the radiator return line 28' via the oil cooler 32 '.

If, when the coolant is heated, the thermostat 29 opens, the path is released via the radiator supply line 24 'to the radiator 26'. At the flow through the turbocharger 1 'nothing changes.

When switching off the internal combustion engine 45, the flow through the turbocharger 1 'from the turbocharger feed 2' to the turbocharger return 3 'finished. In the interior of the turbocharger 1 ', gas bubbles are formed which escape via the turbocharger feed 2' to the T-piece 6 'and from there via the degassing line 8' to the upper side of the expansion tank 9 '.

The escaping gas bubbles / coolant mixture is replaced by the output line 5 'nachströmendes coolant.

In this configuration, the flow direction of the turbocharger 1 'in the normal operating state of the internal combustion engine 45 is reversed to the flow of coolant with the internal combustion engine stopped when gas bubbles form inside the turbocharger 1'. For this purpose, the opening for the turbocharger feed 2 'can be arranged at a geodetically greater altitude than that for the turbocharger return 3'. The water level 10 'is then at a higher altitude than the turbocharger return 3'. As a result, supply and replenishment of coolant to the turbocharger 1 'are ensured if coolant therein is emptied due to gas bubble formation in the expansion tank 9'.

Unlike in the embodiment according to FIG. 1 and FIG. 2 Nor does a continuous convection flow occur when gas bubbles form inside the turbocharger 1 '. Not only because of this, but also because of the through the flow restrictor 43 'limited flow through the turbocharger 1', this version offers a turbochargers, which are only a limited thermal load. For this embodiment has advantages in terms of compactness in the arrangement of the components provided for the coolant circuit. A particularly space-saving design is hereby made possible.

In another, not shown here, but particularly space-saving embodiment, the output line 5 'at the turbocharger return 3' is not connected to the radiator return line 28 ', but to the Heizungsradiator return line 37'. At the flow through the turbocharger 1 'thereby nothing changes. The coolant in the turbocharger 1 'is drawn via the output line 5' in the Heizradradator return line 37 ', due to the action of the water pump 18', which communicates via the oil cooler 32 'with the Heizradradiator return line 37'.

LIST OF REFERENCE NUMBERS

1

turbocharger

2

Turbocharger Forward

3

Turbocharger return

4

supply line

5

output line

6

Tee

7

Return line

8th

degassing

9

surge tank

10

water level

11

compensation line

15

internal combustion engine

16

First cylinder row, cylinder block

17

Second cylinder bank, cylinder block

18

water pump

20

Water pump input port

21

First water pump outlet

22

Second water pump outlet

23

quill

24

Radiator supply line

25

Radiator Lead

26

radiator

27

Radiator return

28

Radiator return pipe

29

thermostat

30

Water pump line

31

Short-circuit line

32

oil cooler

33

Heating radiator

34

Oil cooler inlet pipe

35

Oil cooler drain line

36

Heating radiator supply line

37

Heating radiator return pipe

38

compensation line

39

vent line

40

gas pipe

41

Coolant line

42

Coolant outlet

43

supply flow restrictor

44

Entgasungsdrossel

45

internal combustion engine

46

cylinder bank

Claims (10)

1. An internal combustion engine (15; 45), comprising a turbocharger (1; 1'), a cooling medium circuit and a compensation tank (9; 9') for the cooling medium circuit, wherein the cooling medium circuit has the following features:

   - a water pump (18; 18') with a water-pump input connection (20, 20') and with an output connection (22, 23; 22') for circulating the cooling medium, with the water-pump output connection (22, 23; 22') having a higher pressure level in operation of the water pump (18; 18') than the water-pump input connection (20, 20');

   - a radiator (26, 26') for cooling the cooling medium, with the radiator (26, 26') being included in the cooling medium circuit via a radiator flow pipe (25, 25') for the supply of hotter cooling medium and via a radiator return pipe (27; 27') for discharging cooling medium cooled in the radiator (26, 26'),

   with the turbocharger (1; 1') being connected to the cooling medium circuit via a turbocharger flow pipe (2; 2') for supplying cooler cooling medium and via a turbocharger return pipe (3; 3') for discharging cooling medium heated in the turbocharger (1; 1'), with the turbocharger flow pipe (2; 2') branching off from the cooling medium circuit between the water-pump output connection (21, 22; 21') and the radiator flow pipe (25, 25'), and with the turbocharger return pipe (3; 3') opening into the cooling medium circuit in a region of the cooling medium circuit between the radiator return pipe (27; 27') and the water-pump input connection (20, 20'), and with the turbocharger return pipe (3; 3') or the turbocharger flow pipe (2; 2') being in connection with the compensation tank (9; 9') via a degassing line (8; 8'), with the degassing line (8) branching off from the connecting line in the region of the highest point of the connecting line between the turbocharger return pipe (3) or the turbocharger flow pipe (2') and the cooling medium circuit, and with the water level (10; 10') of the compensation tank (9; 9') being located higher than the turbocharger return pipe (3; 3') or the turbocharger flow pipe (2; 2').
2. An internal combustion engine according to claim 1, characterized in that the turbocharger flow pipe (2; 2') is connected to a cooling medium line extending in the region of an engine block (16, 17; 16') of the internal combustion engine (15; 45).
3. An internal combustion engine according to claim 2, characterized in that the turbocharger flow pipe (2') is connected to a thermostat housing (29') attached to the engine block (16').
4. An internal combustion engine according to claim 2, characterized in that the turbocharger flow pipe (2) is connected to a cooling medium duct extending in the engine block (17).
5. An internal combustion engine according to one of the preceding claims, characterized in that the turbocharger return pipe (3; 3') opens into a heating-radiator return pipe (37; 37') further connected to the cooling medium circuit.
6. An internal combustion engine according to claim 5, characterized in that the turbocharger return pipe (3) is connected to the heating-radiator return pipe (37) between a point where the heating-radiator return pipe (37) opens into a heating radiator (33) and a point in which the heating-radiator return pipe (37) opens into a thermostat (29).
7. An internal combustion engine according to one of the preceding claims, characterized in that the turbocharger return pipe opens into a water-pump return pipe which is further connected to the cooling medium circuit.
8. An internal combustion engine according to one of the preceding claims, characterized in that the turbocharger return pipe (3') opens into a oil-cooler feed pipe (28') which is further connected to the cooling medium circuit.
9. An internal combustion engine according to one of the preceding claims, characterized in that the line to the turbocharger flow pipe, the line from the turbocharger return pipe and/or the degassing line are each provided with a throttle (43, 44; 43', 44') for setting the flow resistance for the cooling fluid.
10. A motor vehicle with an internal combustion engine according to one of the preceding claims.

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